Office of External Affairs
Mountain-Prairie Region


U.S. Fish and Wildlife Service
Mountain-Prairie Region
134 Union Boulevard
Lakewood, Colorado 80228

April 4, 2011

Contact: Beth Dickerson 406-449-5225 ext 220


Meltwater Lednian Stonefly Designated

a Candidate for Endangered Species Protection

The U.S. Fish and Wildlife Service has determined that the meltwater lednian stonefly (Lednia tumana) warrants protection under the Endangered Species Act (ESA), but that proposing the species for protection is precluded by the need to address other high priority species.    Our comprehensive review — known as a 12-month finding —determined that there is sufficient scientific data to warrant listing the species in the contiguous United States. However, we are precluded from beginning work immediately on a listing proposal because our limited resources must be devoted to other higher priority actions.

We added the meltwater lednian stonefly to the list of candidate species and will review its status annually. When a "warranted but precluded" finding is made for a species, it is classified as a candidate for listing. If we propose the meltwater lednian stonefly for protection under the ESA in the future, the public will have an opportunity to comment. 

The meltwater lednian stonefly (Lednia tumana) is an aquatic insect in the order Plecoptera (stoneflies).  Stoneflies are primarily associated with clean, cool streams and rivers.  Juvenile meltwater lednian stoneflies are found in snow-melt runoff streams in high elevation, alpine and subalpine streams, most typically in locations closely linked to glacial runoff.  The species is generally restricted to streams with mean summer water temperature less than 10 degrees Celsius (oC) or 50 degrees Fahrenheit (oF).  The meltwater lednian stonefly is found in only a few locations within Glacier National Park, Montana. 


During the review, we determined that habitat loss and modification resulting from the melting of glaciers in Glacier National Park is the greatest threat to the species. The shrinking of glaciers in Glacier National Park has been documented during the past 100 years, and nearly all glaciers are predicted to be gone from the Park by 2030.  Higher water temperatures, seasonal or permanent stream dewatering and changes in the timing and volume of snowmelt are likely to change the stonefly’s habitat such that it no longer satisfies the species’ needs.  The species occurs on National Park Service lands, which protects its habitat from direct destruction or modification resulting from most human activities.  However, existing regulatory mechanisms do not address environmental changes due to global climate change, which is the primary cause of the loss of glaciers and resulting threat of habitat loss and modification for the species.


In the same 12-month finding, we also found that two undescribed species of mountainsnail – the Bearmouth and Byrne Resort mountainsnails (genus Oreohelix) from Montana – do not warrant protection under the Act.  The Bearmouth mountainsnail and Byrne Resort mountainsnail are terrestrial mollusks commonly called “mountainsnails.”  Because these mountainsnails are not recognized as species by the scientific community, they are not listable entities as defined by the ESA.  Since we have concluded that the two petitioned mountainsnails are not listable entities, an analysis of threats is not required under the ESA.  Therefore, we will take no further action with these species at this time.

The Service made these three determinations in response to a petition filed July 24, 2007 by Forest Guardians (now WildEarth Guardians) requesting that 206 species ranked as G1 (critically imperiled) or G1G2 (critically imperiled or imperiled) by the organization NatureServe be listed as threatened or endangered under the Act.   We completed an initial review of these three species on August 18, 2009 and concluded that the petition contained substantial information supporting a full study of the status for meltwater lednian stonefly, Bearmouth mountainsnail, and Byrne Resort mountainsnail.

A copy of the finding and other information about the meltwater lednian stonefly, Bearmouth mountainsnail, and Byrne Resort mountainsnail is available on the Internet at or by contacting the Montana Field Office at 406-449-5225.


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